1. Field of the Invention
The present invention relates to display devices and methods, and in particular, to using reflected light to project a moving design.
2. Description of Related Art
Light is often projected for decorative, aesthetic, or amusement purposes. A spotlight can shine through a rotating wheel having different colored segments to produce a light beam with time-varying colors. A spotlight can shine on a rotating globe covered with a mosaic of mirrors to project multiple light beams that circulate around a room, such as a dance floor. More sophisticated light shows have used laser beams that trace out highly complex patterns using computer-controlled beam displacement.
Shadow plays are performed by projecting the shadows of puppets and other characters to form silhouettes on a projection surface. Also, a simple slide projector uses a projection lamp, transparency, and biconvex lens to project an image of the transparency onto a screen.
Various devices exist for changing or redirecting light. For example prisms are used to take an incident light beam and redirect it at an angle depending upon the color of the incident beam. For sunlight, the prism can separate the colors into the well-known color spectrum. This prismatic effect can be seen in various jewel cuts or in faceted crystal elements hanging in a chandelier. Other complex light effects can be produced by simple diffraction gratings or by a known holographic diffraction grating film.
Light is often redirected for utilitarian purposes. Rotating lights on emergency vehicles and traditional lighthouses are two well-known examples. Light can also be projected for educational purposes as in a planetarium.
Sunlight is often used for decorative and aesthetic reasons. Stained-glass windows illuminated by sunlight provide an attractive colored image, although that image is located only at the window. Nature also provides its special light shows with the rainbow or with the sparkling effect produced by light reflected from the ripples in a stream.
See also U.S. Pat. Nos. 2,758,502; 2,814,029; 3,621,133; 3,767,299; 4,196,461; 4,764,850; 4,952,502; 5,906,427; 5,934,223; 6,113,458; 6,145,228; 6,793,355; 6,958,869; 7,153,022; 7,182,472; D396,122; D424,230; and D521,173.